The tape cartridge of the Von Behren patent, U.S. Pat. No. 3,692,255, incorporated herein by reference, includes a housing defining a thin, generally rectangular enclosure. The housing contains a length of magnetic recording tape which is wound upon a pair of tape reels. The magnetic recording tape is driven by an elastomeric drive belt which, in turn, is driven by a single reversible drive motor. The drive belt provides rapid acceleration and deceleration of the recording tape in either direction. The drive belt is stretched along a drive belt path generally defined by a drive roller, a pair of guide rollers, and part of the tape pack wound on each reel.
As the drive belt travels over the various rollers and the tape pack of the von Behren tape cartridge, the drive belt most preferably remains in a centered position on these surfaces. However, the drive belt has a tendency to shift away from a centered position. In the absence of a restraining force, the drive belt could run over the edge of a roller, causing catastrophic failure of the tape cartridge. To help prevent the drive belt from shifting away from a centered position, the rollers have been configured with a crown to provide a centering moment. See, e.g., von Behren et al., Adv. Info. Storage Syst., "Mechanical Design of a Belt-Driven Data Cartridge", Vol 1, pp. 49-59 (1991)
Previously known drive belts have been characterized by a flat geometry. A flat geometry drive belt is formed by first punching or cutting an annular ring from a suitable polymeric sheet. The ring is then stretched and distorted into a belt shape for insertion into a tape cartridge. See, e.g., col. 2, lines 57-63 of U.S. Pat. No. 4,466,564. This approach, unfortunately, generates substantial quantities of waste. Much of the polymeric sheet has to be discarded after rings are punched or cut from the sheet.
The quality of magnetically reproduced and recorded information depends, in part, upon precise, accurate tracking of the drive belt during transport (i.e., during playback, recording, fast forwarding, and rewinding). Any irregularities in drive belt tracking can adversely affect recording and reproducing performance.
Tape tensioning characteristics depend, in part, upon the surface texture of the drive belt. If the surface of the drive belt is too smooth, then air tends to become entrapped between the magnetic recording tape and the drive belt as the drive belt moves. When this happens, tape tension is difficult to control. Mechanical instabilities usually result. These instabilities may cause misregistration between a recorded data track and subsequent reading operations, leading to possible signal loss and data errors. See, for example, D. P. Smith, "Influence of Speed on Tape Winding in Data Cartridge Tape Systems", Proceedings of the Japan International Tribology Conference, pages 1899-1903 (1990). To avoid this problem, a drive belt has typically been made with textured surfaces to allow air to escape from under the moving drive belt. See, e.g., U.S. Pat. Nos. 4,466,564 and 4,581,189.
The demand for higher capacity storage systems is increasing. As this demand increases, the demand for faster data transfer rates also increases. Faster data transfer rates require that the drive belt starts, stops, and runs at faster rates as well. Tracking characteristics, however, tend to deteriorate at such faster rates. Accordingly, there continues to be a need for improved drive belts that provide better tracking characteristics at faster data transfer rates.